The human use of material objects differs from that of nonhuman primates in having elaborated task specialization among the participants in the building of constructions, and the use of constructions to represent things not immediately present to the builders. This type of activity is common among children from 3 to 5 years of age, and videotape records of such cooperative constructive play will be made in two constrasting cultural settings: in a Western preschool in Australia and among a hunting and gathering group in Malaysia. The records will be used as raw data for frame-by-frame analysis with the aim of describing the behavioral units that comprise this activity. It is anticipated that this method will reveal both the cues used to sustain the cooperative use of tools and the behavioral units most useful for comparing human object use both cross-culturally and to the object use of other primate species.